Filling a bladder tank in the dinghy to transfer to your onboard tank is easy. You fillit the same way you fill the jerry cans (usually from a water spigot or hose). The advantage is, the bladder tank rolls up small when empty. And can carry quite alot of water when full. It also will/can lie in the bottom of the dinghy easier than the jerry can balancing act (sliding around etc.
Getting the same type of pump as you already have aboard is a good idea, however your pressure water system pump probably is prety costly and not durable enough to be kncked about in a dinghy and possibly inclimate weather conditions.
Harbor freight sells a 12 volt stainless pump body model for about $30 with standard hose fittings it can be attached easily to the bladder tank.
I guess if you didn't have a bladder tank you could still fill the jerry cans then pump into the main tank, untill you convinced yourself that this method is worthy . Then I would guess you would tire of lugging the cans and just get the bladder tank.
ALso to the sailor asking about mooring locations. why not just anchor ? it's free ! and you never have to wonder what your actually tied to when the weather kicks up, as you will have lowered the ground tackle yourself.